.clearfix:before,
.clearfix:after {
    content: "";
    display: block;
    clear: both;
}
.fl {
    float: left;
}
.fr {
    float: right;
}
.al {
    text-align: left;
}
.ac {
    text-align: center;
}
.ar {
    text-align: right;
}
.hide {
    display: none;
}